Here is one that does the upload, the database and delete should be easy from there
http://net.tutsplus.com/tutorials/php/codeigniter-from-scratch-file-uploading-and-image-manipulation/
Also review the codeigniter pages for this subject
Also of note
Codeigniter: Image Upload
EDIT----------------------------------------
I am assuming you are listing the images in a table to edit or delete them. I could be way off base with what you are doing. I am also assuming while you use the "user id" you also assign an id to the image itself.
For deletions I do something like this
$this->table->set_heading('Date', 'Title', 'Delete', 'Update');
foreach($records as $row){
$row->title = ucwords($row->title);
$this->table->add_row(
$row->date,
anchor("main/blog_view/$row->id", $row->title),
anchor("main/delete/$row->id", $row->id, array('onClick' => "return confirm('Are you sure you want to delete?')")),
anchor("main/fill_form/$row->id", $row->id)
);
}
$table = $this->table->generate();
See the second anchor? It picks up the ID of the image in the db and points to a controller function:
function delete()
{
$this->is_logged_in();
$this->post_model->delete_row();
$this->maint();
}
the Model
function delete_row()
{
$this->db->where('id', $this->uri->segment(3));
$this->db->delete('posts');
}